Fitter Error for fractional PLL - Fitter Error for fractional PLL The error in fitting is as follows. Going thorugh the knowledge base, not clear what the solution is. It says "Location FRACTIONALPLL_X0_Y38_N0" already occupied. I can move to different location but not sure what constraint syntax is. Maybe others have seen the same issue. Error (14566): The Fitter cannot place 1 periphery component(s) due to conflicts with existing constraints (1 fractional PLL(s)). Error (175001): The Fitter cannot place 1 fractional PLL, which is within PLL Intel FPGA IP CPU3000Qsys_pll. Info (175028): The fractional PLL name(s): CPU3000Qsys:u0|CPU3000Qsys_pll:pll|altera_pll:altera_pll_i|general[0].gpll~FRACTIONAL_PLL Error (11238): The following 1 fractional PLL locations are already occupied, and the Fitter cannot merge the previously placed nodes with these instances. The nodes may have incompatible inputs or parameters. Error (11239): Location FRACTIONALPLL_X0_Y38_N0 is already occupied by CPU3000Qsys:u0|CPU3000Qsys_ddr2:ddr2|CPU3000Qsys_ddr2_pll0:pll0|pll1~FRACTIONAL_PLL. Error (12289): An error occurred while applying the periphery constraints. Review the offending constraints and rerun the Fitter. Replies: Re: Fitter Error for fractional PLL It looks like you have incremental compilation enabled for the entire design, locking down the placement and routing. That would prevent you from making a change like this. Check the Design Partitions window. Replies: Re: Fitter Error for fractional PLL Device is Cyclone V (5CEFA4F23C7). Quartus Standard version 18.1. There are no IO pin conflict looking thorough the QSF file (attached) The IPs are many DDR2 has pll and NIOS pll, pll reset monitor. Replies: Re: Fitter Error for fractional PLL What device family and Quartus version and edition (Standard, Pro) are you using? What IP are you using that might be conflicting with the use of a particular PLL? Have you made I/O pin assignments that might be conflicting?